Diagnosis

a prior episode of paralytic polio confirmed by medical history, neurologic examination, and, if needed, an electrodiagnostic exam to show changes consistent with prior anterior horn cell disease (exam is not required for limbs with obvious polio paralysis);

a period of neurologic recovery followed by an extended interval of neurologic and functional stability, usually 15 years or more, preceding the onset of new weakness;

the gradual or abrupt onset of new weakness and/or abnormal muscle fatiguability (decreased endurance), with or without generalized fatigue, muscle atrophy, and/or pain; and

exclusion of medical, orthopedic, and neurologic conditions that may be causing the health problems listed above. New weakness (usually accompanied by diminished function) is the cardinal symptom of post-polio syndrome.

Without a clear history of new weakness, the diagnosis cannot be made. In addition, the diagnosis cannot be made without excluding other likely causes of new weakness and other new health problems. For this reason, post-polio syndrome is called a diagnosis by exclusion.